FIG. 1 exemplifies a configuration of a computer apparatus which is connectable with an expansion card. One of program groups for controlling each device of the computer apparatus is Basic Input/Output System (BIOS). On the other hand, the functions of information apparatus such as the computer apparatus are expanded by adding an expansion card or an external apparatus via an expansion card. The expansion card installed in the computer apparatus is controlled by using a computer program for controlling the input/output which is called expansion Basic Input/Output System (expansion BIOS). Hereinafter, BIOS which handles the control of each device included in the basic configuration of the computer apparatus is defined as basic BIOS.
Basic BIOS is stored in a Read Only Memory (ROM) on a motherboard for example. Here in FIG. 1, the ROM is included in the memory. On the other hand, BIOS for expanding the basic BIOS for controlling devices which the basic BIOS does not handle is referred to as expansion BIOS. The data image of the expansion BIOS is generally stored in a storage component such as an EEPROM on the expansion card. Hereinafter, the data image of expansion BIOS is referred to as expansion BIOS data. When the computer apparatus is booted, the computer apparatus uses basic BIOS to search expansion BIOS in the storage component of the expansion card. Then, the computer apparatus transfers the expansion BIOS onto the memory to make the expansion BIOS available.
FIG. 2 illustrates the process flow in the computer apparatus as illustrated in FIG. 1. For example, the computer apparatus is booted by a boot operation by a user etc. (S501). When the computer apparatus is booted, the basic BIOS is called, first, the initialization of the Central Processing Unit (CPU) and the memory and the like is performed, and next, resources are allocated to each equipped device (S502). Here, for example, the initial settings for the register values of the CPU such as zero clearance exemplify the initialization. Additionally, the address setting for the areas used as registers to the equipped devices in which the memories are used as registers exemplifies the resource allocations to the equipped devices. Hereinafter, when the CPU performs processes according to computer programs such as the basic BIOS, it merely explained that the computer programs such as the basic BIOS perform the processes.
When the resource allocation to each device is completed, the basic BIOS searches for the expansion BIOS in the storage component of each expansion card which is connected with the computer apparatus (S503), and then transfers each expansion BIOS onto the memory of the computer apparatus (S504). Each expansion BIOS performs the initialization, the initial setting and the control of the corresponding expansion card (S505).
And then the basic BIOS boots the Operating System (OS) (S506). For example, it is assumed that the configuration is employed in which an expansion card is connected with a storage apparatus. When the basic BIOS of the computer apparatus read out data from the storage apparatus connected with the expansion card, the computer apparatus obtains the expansion BIOS in advance in S503 and S504 and uses the expansion BIOS to control the expansion card. Otherwise, when the expansion BIOS is not used, the basic BIOS of the computer apparatus fails to read out data from the storage apparatus connected with the expansion card.